1. Field of the Invention
The present invention generally relates to medical implants, and more specifically relates to tissue reinforcing implants.
2. Description of the Related Art
The use of tissue reinforcing implants, such as polymer meshes, is widespread. In 1995, a procedure was developed by F. Ugahary that combines the advantages of pre-peritoneal mesh fixation with the convenience of using small incisions for forming access openings.
Laparoscopic techniques have been developed for repairing inguinal hernias. One technique uses a trans-abdominal pre-peritoneal mesh-plasty (TAPP), whereby an implant mesh is preperitoneally positioned through a trans-abdominal laparoscopic access opening. Another technique is totally extra-peritoneal pre-peritoneal mesh-plasty (TEP), in which a large mesh is laparoscopically applied via an extra-peritoneal access opening. The implanted mesh covers all three potential hernia openings. Often, after the intraperitoneal implantation of polymer meshes, adhesions of internal structures occur, such as intestine, omentum, etc. Thus, there have been many efforts directed to providing implants that prevent, reduce the intensity of and/or minimize adhesions in the area of the implant, both in the center and in the periphery.
Tissue reinforcing implants, commonly referred to as areal implants, have been developed that match or compliment the mechanical properties of the underlying tissue. Orienting the areal implant relative to the underlying tissue may be important because both the target tissue and the implant have mechanical properties that are anisotropic. One example of an implant having anisotropic properties is a mesh with reinforcing fibers running in only one direction.
There are a number of problems associated with convention implants. For example, conventional implants may require surgeons to place alignment mark on the meshes for aligning the meshes on patients. The alignment marks are made using a skin marker that may easily wash off. In addition, after the implantation of polymer meshes, adhesions of internal structure often occur (e.g. intestine, omentum, etc).
Commonly assigned U.S. Pat. No. 7,615,065 to Priewe et al. discloses an areal implant that has a long-term, stable, mesh-like base structure with pores of a size in the range of 1.5 mm to 8 mm and is provided, at least in part, on both sides, with a synthetic, resorbable polymer film. The two polymer films are glued or welded together in the pores of the base structure. The implant disclosed in Priewe reduces the formation of adhesions of internal structures in human or animal organisms, and, after a period of time, facilitates tissue in-growth.
WO 2003/037215 discloses an areal implant having a mesh-like basic structure, and an alignment marking in a central region that indicates the center of the implant. A marking line runs through the central marking. The central marking and the marking line running through the central marking are used for aligning the implant over a surgical opening for reinforcing the tissue.
In spite of the above advances, there remains a need for tissue reinforcing implants having anisotropic properties (e.g. elongation behavior) to simulate the anisotropic properties of the supported tissue (e.g. abdominal tissue). There also remains a need for tissue reinforcing implants that minimize or eliminate the occurrence of adhesions. In addition, there remains a need for tissue reinforcing implants having durable alignment markers. There also remains a need for tissue reinforcing implants that may be used for intra-peritoneal or laparoscopic applications, which fit through a trocar, that are simple to deploy, that may be fixable with sutures, tacks, or glues, and that have a mesh construction.